Yes, it is possible that finest particles go through the filter when solution is hot i filtered using my regular method of nylon cloth (thick ) that is also called PP filter cloth.The AR itself is not interesting in this setting, even though the milkiness may be from Metastannic acid.
Did the powder change after the AR?
The Metastannic acid in this setting would have formed in the Nitric stage.
Metastannic acid is notoriously hard to filter so it should be very obvious that it is that.
Te finest particles may go through, what kind of filter do you use?
Edit for clarity
Powder is quite same after AR.
Only white powder residue remains on filter.
If finest particles goes through filter how they precipitate with gold?